Rifling device



M. RAMSAY RIFLING DEVICE.'

Feb. l0, 1959 Filed May 6, 1957 2,872,720 nlrrrNG nEvIcE MarcusRamsay, New Haven, Conn., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Application Mays, 1957, senat No. 657,212

2 claims. (C12Q- 1.1)

This invention relates to the art of rifiing gun barrels and in particular to a novel apparatus adapted to back up a riing tool frequently referred to as a button The invention also relates toa process practiced by the operation of the apparatus.

killing may be accomplished by advancing a smooth bore barrel over a small torpedo-like forming tool; the barrel is rotated while it is advanced to generate the desired lead angle in the rilling.

Alternative arrangements include maintaining the barrel stationary, driving or pulling a button through the barrel, and revolving the button or barrel as necessary to generate the riiling.

In the former arrangement wherein the barrel is advanced over the button considerable diculty is experienced in backing up the buttonwhile the barrel is being advanced. The problem is particularly bothersome when rifling small caliber barrels because there is not sutlcient space (cross sectional area) to provide adequatesupport to hold the button rigid and immovable, axially, while the barrel is being rotated over the button.

Accordingly, it is a particular feature of the present invention to provide a novel apparatus for backing up a riding button while the element tobe ried is beingV advanced over the button.

Another object of the invention is the provision of a rigid support for a riing button especially adapted to riile barrels having small bores.

An apparatus embodying certain features of the present invention may comprise a table, a tube rigidly mounted to the table, a rod disposed in the tube, key means for securing the rod to the tube, a second tube disposed within the rst tube and surrounding the rod, said second tube being formed with elongated openings for receiving said key means and said second tubebeing movable along the longitudinal axis of the rod and within limits defined by said slotted openings.

The process practiced by the operation of the apparatus of: the present invention may include the steps of providing a button rifling tool operable to form rifling in a bore, holding the tool immovable, advancing a bored barrel over the tool and rotating the barrel While it is advanced so as to create rifling having a predetermined lead.

Other features and advantages of the present invention will become more apparent from the succeeding specification in which:

Fig. 1 is an elevational view of a back up apparatus utilizing the principles of the present invention with certain portions thereof broken away for clarity. This iigure shows a barrel ready to be advanced over the button;

Fig. 2 is a showing similar to Fig. 1 and illustrates the disposition of the various elements of the apparatus after the bored barrel has been ried;

Fig. 3 is a view of the guide tube;

Fig. 4 is a view of the back up rod'and key;

Fig. 5 shows the riing tool;

Fig. 6 is a plan view of a portion of Fig. 1 as viewed in the plane of line 6 6; and,

Fig. 7 is a sectional view of Fig. 1 as viewed in the plane of line 7--7.

Referring now in detail to the single sheet of drawings there is shown a table 10 having a pair of rigid support members 11 and 12 carrying a tubular casing 13. The casing 13 is rigidly secured to the support 11 by a suitable fastener, such as the set screw 14. Disposed within the casing 13 is a back up rod 16 formed with a suitable slot for receiving a key 17.

The key is received in a corresponding pair of slots 19 (Fig. 6) formed in the casing 13 and acts to tie or lock the push rod to the casing thereby preventing relative motion of the rod with respect to the casing, especially along the longitudinal axis thereof.

Disposed in the annular space between the rod 16 and the interior of the casing 13 is a guide tube 21 formed with a pair of opposed elongated slots 22. As is apparent from the drawings, the slots 22 receive the key 17 and the guide tube 21 is free to move to and fro along the longitudinal axis of the back up rod, its stroke being limited by the length of the slots. In other Words, the guide tube is movable from the position shown in Fig. 1 wherein the end 24 of the slot is adjacent the key 17 to the position shown in Fig. 2 wherein the opposite end 26 of the slot is shown adjacent the opposite side of the key. There is a neat sliding tit between the guide tube and the rod.

A reference to Fig. 1 will reveal that la bar, indicated generally by the reference numeral 27', is. also received within the left end of the casing 13. The prime function of the bar 27 is to return the guide tube 21 to the position shown in Fig. l from the position shown in Fig. 2. Obviously, this occurrence may be accomplished by any manual or automatic means.

Referring now to the right end of the apparatus, it is noted that the casing 13 is formed with a projecting lip 23 which acts to support the left end of a bored barrel, representing the work piece, referred to hereinafter by the reference numeral W. A trilling tool or button 2li formed with a plurality of forming surfaces in a well known manner is shown disposed in the forward end of the guide tube with the stem 29 thereof abutting the forward end of the back up rod 16.

If desired, the button may be keyed to the back up rod to prevent rotation of the button with respect to the rod as the barrel is moved over the button; usually` keying is not necessary because the friction between the rod and the stem is sucient to overcome the tendency for the button to rotate.

In the extreme right end of the table a support member 30, rigidly secured to the table 10, carries a dog 31 adapted to engage a threaded ram 32. The ram is movable in the direction shown by the arrow by suitable means such as a lead screw or a hydraulic piston and the dog 31 is effective in cooperation with a thread 33 to develop a predetermined angle of lead as the ram is advanced.

The forward end of the ram carries a coil spring 34 adapted to maintain a slidable collar 36 spaced from the face of the ram by the engagement of a lug 37, depending from the sleeve, with a mating keyway 38 formed in the ram.

The sleeve 36 is movable manually to the right to receive the work piece and upon release snaps to the position shown. Thus, it is apparent that the work piece W is supported at one end by the lip 23 of the casing 13 while the opposite end is carried by sleeve 36 supported in the ram 32. It is to be noted that the Patienten Feb. re, lesev ram is formed with a cut out portion 39 and is utilized to receive the button after the rifle has been passed completely over the tool as show-,u in Fig. 2.

The apparatus operates in thefollowing manneri.

.Assume that a work piece. W is disposed` in Vthe apparatus as shown in Fig. l. The application of force to ,the ram 3.2 in the direction shown by the arrow of Fig. l by a hydraulic piston 41 (Fig. 2.) or other suitable propelling devicev will cause the work piece W to Lpass. over tool 28'. Asl the workpiece is. driven .to the left Athe dog 311 byvirtue .of its .engagement with the thread 33., will impart rotation. to the .work piece. in accordance with the lead .angle .of the thread d3. The ram 'is not shown keyed to the work .and keying is usually not necessary because. of theccnsidera'ble friction:` existing between corresponding. faces .ci .the ram and the. work piece. lf- .slippage does occur usually formation. of several punch marks on one or the other opposed faces. is s uiicient to prevent slip.

As the work W advances overthe `tool 28. the left end of the work encounters the guide tube 21. The guide tube is dri-.ven along axially relative to the back up rod 16 and the tool until the work piece has passed completely over `thetoofl and arrives at the position shown .in Fis. 2.

It is tob e noted that the pressure applied to the push rod i6 `is of the ,order of 54,000 `p. s. i. and may .be .as high. as 150,000 p.` s. i. .in cases of abore correspond ing to a 22 caliber ritle., this frequently represents a totalV load or. thrust upon the push rod ranging from 2000 lbs..

to 5555 lbs.. Such a load would .buckle the rod except for the consistent support against buckling afforded by the guide tube 21. Y

Note further that as `the guide `tube is driven. along th rod 16 by the wor-k piece, the work piece replacesr the tube and provides lateral support for the rod 16. In this fashion,.resistance against bucklingvis provided .constantly.

,As stated previously, the .cavity 39 is provided in the ram 32 to insure complete traverse lof the tool through the barrel and in this connection it is noted that. .the lip 27 is operative to engage andv move the sleeve 36;, compressing the spring .34 thusavoiding interference between the sleeve and the lip.

The method and `apparatus of the .present invention have `distinct advantages over other riliing schemes.

For example, frequently .a button is pulled .through a bored barrel to accomplish rimng. This method has inherent disadvantages whereby .the pulling force is limited by 4.(1) lovv tensile. strength of .the .button itself (2.) lOw tensile strength ofthe joint between the. button and the pull=rod.and1.(3v)y. low tensile strength betweenthe rodand thechuck utilized to pull the rod.

Since in the present invention the button is held rigid while the work piece is pushed over the rod, none of the above disadvantages exist. T he force utilized in advancing the barrel over the button is not limited by the above-noted tensile failures and can be as high as the compressive strength of the button and its back up" fixture. Inherently, the compressive strength of a given structural metal, such .as steel, is far in excess of its tensile strength.

Obviously many varia-tions and modifications may be made in the apparatus and process of the present invention without departing from the spirit and scope thereof.

What .is claimed is:

l. in a machine for riing 22 caliber gun barrels wherein the barrel is advanced over the riing tool, a tixture for backing up the tool. comprising a table, a casing rigidly mounted to the table, a rod disposed in the casing, key .means for locking. the rod to the casing .to

preclude, relativer motion therebetween, va guide tubedisposed within thecasing and snugly surrounding the rod to support the rod against lateral bending, said guide tube being formed with a pair ,of opposed clongate openings for receiving said. key means and said guide tubebeing movable relative to the rod in reciprocatory fashion along the longitudinal axis of the rod, said barrel being operable to support the rod as the guide tube is moved.

2. In .a machine for riing 22 caliber gun barrels` wherein `the barrel is advanced over the ritling tool, a fixture for backing up the tool .comprising a table, a tubular casing rigidly mounted to the table, a back up rod centrallyv disposed in the casing, key means for locking the rod to the casing to preclude relative motion References Cited in the file of this patent UNITED STATES PATENTS 1,962,944 Spatta June l2, 1934 2,609,631 Garand Sept. 9, 1952 2,732,932 Strock Jan. 31, 1956 2,810,185 Simons Oct. 22, 1957 FOREIGN PATENTS 118,253 Australia Mar. 8, .1944 

